Unit 14: Avian Health Management

Dr. Rob Porter
Indiana Veterinary Diagnostic Laboratory
Fishers, IN
Phone (317) 579-6353 

Part I -- Background Information on Poultry

Common Categories of Poultry

Broiler breeders

Most birds are hybrids; cross of White Plymouth Rock vs. Cornish breeds

• The birds are bred to produce final progeny that are broilers for consumer
• The mature hen weighs 6-9 lbs; comes into production around 25-28 weeks and peaks in egg production at 30-34 weeks.
• The mature male weighs 10-13 lbs
• 170-185 eggs are produced per bird per year, with feed ratio of 7-8.5 lbs consumed per 1 dozen eggs
• Breeding ratio is about 10 hens per rooster
• Spent hens (end of laying cycle) sold as "heavy hens"-sold frozen in cry-o-vac bags
• Roosters are further processed in items such as soup
• Spend first 7-8 weeks of life in brooder house and then go to growout house

Broilers

These birds are the progeny of broiler breeders

• They are marketed at about 4-5 weeks of age, weighting 4-4.5 lbs
• Their feed conversion is < 2 lbs of feed per 1 lb of broiler
• These are quality meat products-often further processed for consumer

Commercial layers

These birds are usually leghorn hybrids (white earlobes)

• They lay infertile eggs for human consumption; no rooster is needed
• The mature hen weighs 3.0-4.0 lbs
• The hen comes into egg production from 17-18 weeks of age and peaks around 30 weeks (when 90% of flock is producing eggs)
• The hens are kept for about 14 months (56-60 weeks) of lay and are expected to produce 250-310 eggs over this period
• There is non-restricted feed intake: 22-24 lbs/100 hens per day
• Feed conversion equals 3.5-3.9 lbs of feed per 1 dozen eggs
• Spent hens are sold as "stewing hens" or put into soup
• Many laying flocks are "molted" and brought back into production for 6-8 months

Light breeder hens produce the commercial layers mentioned above

Turkeys (poults are sexually immature male or female turkeys)

• Toms (males) are marketed at 19-20 weeks of age or less and weigh from 28 to 30 lbs at that time
• Hens marketed at 14 weeks of age weighing 14-16 lbs
• Feed conversion is 2.8-3.2 lbs feed per 1 lb of live turkey
• Turkeys are housed in broiler-type houses until 8 weeks of age, then raised in confinement or out on range

Turkey breeders

• Light duration of the day/night cycle is increased on hens at 28-30 weeks of age
• Hens start to produce eggs around 32 weeks of age
• 80 poults are produced per hen in a typical 24 week production period
• All commercial turkey breeders are artificially bred
• After the initial 24 week production period, the hens are usually molted and kept in production for another 15 weeks

White Peking Duck

• it takes 4-4.5 weeks to reach market weight of 4.5 lbs
• breeders are kept on litter
• brooders, H₂0 and feed are provided similar to other poultry, however, ducks drink 4-5X as much H₂0 as chickens
• meat bids may be reared on plastic mesh rather than litter

  Part II -- Poultry Management Practices

Vaccination

Why?

• prevent economic loss due to mobidity/mortality caused by infectious disease
• vaccine response is controlled, predictable, effective, measurable, and safe
• passive(?) and active immunity
• may be given in drinking water, hatchery spray, field spray, eye drop, Beak-O-Vac, wing web stick

Induced Molting

Why?

• toward the end of the first laying cycle, the egg size decreases and shell and albumin quality drop; producer must either sell the hens as spent hens and repopulate with new pullets or molt the hens
• this is an economic decision made by the producer
• it causes cessation of egg production
• it results in increased egg size, improved egg shell and albumin quality when hens resume production

Advantages

• increased production from flock
• increased feed conversion
• decreased mortality
• gives birds a rest from production

Disadvantages

• inhibits cell-mediated immunity
• +/- inhibition of humoral immunity
• prolonged bacteremia in molted hens (Salmonella)

Molting Protocols

• feed deprivation -- most common means of inducing molting
• zinc feeding
• sodium restriction
• drug induced
• decrease day length to less than 11-13 hours light/day in conjunction with feed deprivation

Ventilation

Proper ventilation is very important in the health management of poultry

It is important to monitor ammonia levels and keep levels at less than 25-30 ppm

• high levels of ammmonia -------- > corneal ulcers on eye
• high levels of ammonia --------- > paralysis of respiratory ciliary apparatus of trachea------ > respiratory infection

Pecking order

It is very important to understand this behavioral trait in birds, in order to manage a flock effectively.

• there are separate pecking orders for males and females
• the pecking order is unidirectional and linear
• the pecking order is established between 6 and 10 weeks of age
• establishment of pecking order reduces nonproductive energy expenditure (aggression)
• establishment of pecking order results in predictable social interactions among birds
• the stability of pecking order depends on the bird's ability to recognize other birds in the group

Cannibalism

Causes

• cloacal prolapse
• inadequate feed/water/nest space
• overcrowding
• light too bright
• rooster/hen ratio greater than 1:10
• high environmental temperature
• nutritional deficiency (methionine deficiency --> feather pecking)
• intact beak (beak trimming will decrease/eliminate the problem)

Brooder environment -- Biosecurity is very important in brooder environment as well as other poultry environments!

The time spent in the brooder environment is a critical period for hatchlings; critical features of the brooder environment are:

• light
• feed
• water
• heat

The highest mortality in poultry is experienced during the first 10 days of life (brooder period), and is due to:

• "starve-outs" -- birds that do not eat or drink (cannot find food and water)
• gout-uric acid (nitrogenous waste products) build up in blood stream (due to dehydration)
• aspergillosis, a fungal infection in the respiratory tract
• "navel ill" or "omphalitis" a bacterial infection of the umbilicus or yolk sac remnant of the chick

POULTRY FUN FACTS (Amaze your friends! Be the hit of the next party!)

Human per capita consumption (1990) = 72.2 lbs chicken meat/year compared to 64 lbs/year for beef. Two hundred and thirty-five (235) eggs consumed per person per year.

INDIANA Production Facts

1. Indiana is #4-5 in nation in egg production, with 20 million layers producing 6 billion eggs/year = $300 million/year
2. California is #1 at $433 million/year
3. Indiana is #1 in number of laying pullets hatched each year
4. Indiana is #7 in nation in turkey production, with 15 million turkeys/year = $120 million
5. North Carolina is #1 at $450 million
6. Other top producing states are Minnesota, Missouri, Arkansas, California, and Virginia
7. Indiana is #1 in duck production in U.S.

Vertical Integration in Poultry One Corporation owns everything but primary breeder flock

Definitions

Poultry: Domesticated fowl, including chickens, turkeys, waterfowl, and game birds, except doves and pigeons, which are bred for the primary purpose of producing eggs or meat.

Primary breeding flock: A flock composed of one or more generations that is maintained for the purpose of establishing, continuing, or improving parent lines.

Multiplier breeding flock: A flock that is intended for the production of hatching eggs used for the purpose of producing progeny for commercial egg or meat production or for other nonbreeding purposes.
 

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